1. Field of the Invention
This invention relates to computer systems. In particular, the invention relates to three-dimensional (3-D) input entry devices.
2. Description of Related Art
Three-dimensional (3-D) graphic and imaging systems have been popular for a number of years. High performance processors with 3-D capabilities have been developed for 3-D applications such as animation, visualization, games, and education.
In many interactive 3-D applications, the user needs to interact with the system in a 3-D world. The traditional input entry devices, e.g., mice, tablet digitizers, track balls, only provide two-dimensional (2-D) input information. For example, in a 3-D system having three coordinates (x, y, z), the 2-D input information includes only the (x, y) coordinates. The depth information (the z-dimension) is usually missing. The input data, therefore, does not represent sufficient information to fully utilize the 3-D world as generated or processed by the graphics or imaging programs.
There are a number of ways to process 3-D information in the system. The simplest way is to assume that the depth dimension is constant. In essence, this method ignores the depth information or assigns a predetermined depth dimension. This method is undesirable because it does not provide the user the means to change the depth dimension. Another way is to convert the 3-D world from the program to a 2-D world as seen by the user and process the 2-D input on this 2-D remapped world. This method introduces ambiguity in processing the data. Another way is to provide 3-D input devices and/or subsystems used in virtual reality systems such as gloves, head-mounted display. This method is expensive and requires complex hardware modifications.
Therefore, there is a need in the technology to provide a simple and efficient method to navigate in 3-D worlds.